Strand brake assembly

ABSTRACT

A strand brake assembly for preventing excessive sag in a messenger strand during installation of the strand on supporting poles. The assembly includes a base plate having a strand guide and a brake member cooperating therewith to brake the strand against retrograde movement. The base plate is attached to another plate member which is adapted to be clamped between the clamp plates of a standard strand clamp, spacing the clamp plates apart a distance sufficient to allow a messenger strand to be slidably received within the strand groove defined by portions of the clamp plates. In one embodiment of the invention, the base plate is pivotally attached to the other plate member to provide automatic alignment of the cable guide with a strand passing through the guide and the strand groove of the clamp.

United States Patent 1191 Jackson 1 Oct. 28, 1975 STRAND BRAKE ASSEMBLY[75] Inventor: Richard L. Jackson, Lewisburg,

Ohio

[73] Assignee: Jackson Communication Corporation, Clayton, Ohio [22]Filed: July 26, 1974 [21] Appl. No.: 492,043

24/134 KC, 132 CH, 132 PE, 132 CL, 132 SB, 132 WP, 132 WA 3,364,529l/1968 Blacher 24/134 R Primary Examiner-Donald A. Griffin Attorney,Agent, or Firm-Biebel, French & Bugg 57 ABSTRACT A strand brake assemblyfor preventing excessive sag in a messenger strand during installationof the strand on supporting-poles. The assembly includes a base platehaving a strand guide and a brake member cooperating therewith to brakethe strand against retrograde movement, The base plate is attached toanother plate member which is adapted to be clamped between the clampplates of a standard strand clamp, spacing the clamp plates apart adistance sufficient to allow a messenger strand to be slidably received[56] References Cited within the strand groove defined by portions ofthe UNITED STATES PATENTS clamp plates. in one embodiment of theinvention, the 1,243,103 10/1917 Richardson 24/134 R base P181te isPivotally attached to the other Plate ,3 ll 6/1921 Johnson et a1....24/134 R member to provide automatic alignment of the cable 1,518,85012/1924 Hume 24/134 R guide with a strand passing through the guide andthe 1,705,523 3/1929 Hofbauer 24/134 R strand groove Of the clamp.2,080,700 5/l937 Dale 24/134 R 3,204,309 9/1965 Ricker 24/134 L 9Clalms, 5 Drawlng Flgures IO IO U8. Patent Oct. 28, 1975 l STRAND BRAKEASSEMBLY BACKGROUND OF THE INVENTION In stringing coaxial cable,conventional practice is to lash the cable to a messenger strandextending between adjacent supporting poles. While cable installationcan frequently be accomplished by suspending cables from an existingmessenger strand, in many instances it is necessary to first install thesupporting messenger strand.

When pulling a new messenger strand into place, the strand is trainedthrough strand grooves in clamps mounted on each of the poles. Duringthe strand pulling operation the opposing clamp plates of the clamps arenot tightened into clamping engagement with the strand but instead, theplates are bolted together loosely enough to allow the strand to slidethrough the strand groove defined by the opposing plates.

One serious problem encountered during the installation of a messengerstand as described above, is that the weight of the strand, which can besubstantial, will cause the strand to sag between poles unless it isclamped at each pole. This is generally unacceptable, since saggingstrands will cause blockage of streets, highways and the like over whichthe strand is passing, and is completely intolerable at railroadcrossings. Additionally, a strand left sagging between poles any lengthof time is quite likely to attract children who may be injured byswinging on the strand or cause damage to the strand itself. It willalso be apparent that a strand swinging in a high wind can arc up ontohigh voltage lines.

There are a number of cable and rope gripping devices in the prior art,such as those shown in US. Pat, Nos. 1,898,677; 3,204,309; and3,364,529, some of which are designed for stringing conductors. However,the conventional way of preventing sagging of the messenger strandduring the pulling operation is to station a man on the pole at thestrand clamp where, acting in coordination with the other members of thestringing crew, he alternately tightens and loosens the clamp at whichhe is positioned.

While this is obviously an undesirable situation in that it requires thefull time services of a lineman positioned on the pole and requires arelatively high degree of coordination between the members of thestringing crew, this approach has nonetheless been an accepted one sinceit is a time tested approach to preventing sag during the pullingoperation.

SUMMARY OF THE INVENTION The present invention provides a strand brakeassembly which is mounted on the supporting poles and provides a brakingaction against retrograde movement of the messenger strand, andconsequently, strand sag, during the strand pulling operation.

The strand brake includesa clamp engageable portion adapted to beclamped between the opposing clamp plates of a pole mounted strandclamp.Attached to the clamp engageable portion of the plate is a base plate,carrying a strand guide and a brake which cooperates with the strandguide and permits movement of the strand through the brake in only thepulling direction.

The clamp engageable portion of the brake is provided with an opening oropenings, which receive the bolt or bolts of the pole mounted strandclamp. When in use with a conventional three bolt clamp, the clampengageable portion of the brake is provided with three openings, whichare formed conveniently as notches to facilitate installation andremoval of the strand brake.

The clamp engageable portion of the brake is of sufficient thicknessthat, when clamped between the opposing clamp plates it spaces the clampplates far enough apart to allow the strand being installed to slidewithin the strand groove defined between the clamp plates. The strandguide mounted on the base plate is positioned such that the strand liesin substantially the same plane as it passes through the strand guideand the strand groove.

While the base plate may be rigidly fixed to the clamp engageableportion of the brake, in a preferred embodiment of the invention thebase plate is pivotally attached to the clamp engageable portion forpivotal movement about an axis extending normal to the plane in whichthe strand lies. In this way, the strand guide is self-aligning,positioning itself automatically to accommodate divergencies from astraight line pull into the strand clamp.

As will be apparent from the following description, the presentinvention provides a strand brake assembly which includes a strand brakeof relatively simple and inexpensive construction which can be attachedreadily to a conventional pole mounted clamp to provide a brake assemblywhich prevents effectively sagging of the messenger strand duringpulling operations.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showinggenerally, the installation of a messenger strand;

FIG. 2 is a perspective view of a pivotal strand brake in accordancewith the present invention;

FIG. 3 is a perspective view of a strand brake installed in a polemounted clamp;

FIG. 4 is a cross-sectional view through a pole, clamp and strand brake;and

FIG. 5 is an elevational view of a fixed strand brake.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As seen in FIG. 1 of thedrawings, in a typical strand pulling operation the strand 10 isunreeled from the reel stand 12 and trained over a block 14 at a firstpole 15 and thence through partially opened strand clamps 16 onsucceeding poles 17. A conventional strand clamp, as best seen in FIGS.3 and 4, will include a pair of opposed clamp plates 18 and 20 one ofwhich is provided with a relieved portion 22 to define with the otherclamp plate, a strand groove.

The two plates may be mounted on a pole 17 by means of a through bolt 24provided with washers 26 on opposite sides of the pole and a nut 28which secures the bolt in the pole. The bolt is provided with a secondnut 30 which clamps the clamp plates 18 and 20 together with the strand10 fixed in the strand groove between the two plates. Usually,additional nuts and bolts 32, 34 are utilized to secure the clamp platestogether.

In conventional strand pulling operations the nuts 30 and 34 are backedoff enough to allow the cable 10 to slide within the strand groove. As aresult, a man must be stationed on the pole at the strand clamp toalternately tighten and loosen the nuts to prevent sag between poles.

With the strand brake assembly of the present invention, however, sagbetween poles is eliminated automatically without the necessity ofpositioning a lineman on the pole to actuate manually the strand clamp.Thus, as best seen in FIGS. 2 and 3 of the drawings, a strand brake isprovided which includes a clamp engageable portion 42 and a base plate44.

The clamp engageable portion 42 is provided with openings in the form ofnotches 46, 48 and along its lower edge which are adapted to slide overthe bolts 24 and 32 between the clamp plates 18 and 20. The nuts 30 and34 are then tightened, clamping the portion 42 therebetween and spacingthe plates 18 and 20 far enough apart to allow a strand 10 receivedwithin the strand groove to slide freely.

The base plate 44 may be pivotally attached, as at 52, to the portion 42for pivoting movement about an axis substantially normal to the plane inwhich the strand lies as it passes through the strand brake assembly. Abrake lever 54 is pivotally mounted on the base plate at 56 and carriesa brake shoe 58 having a strand engaging portion 60.

A strand guide 62 is also mounted on the base plate and has a strandengaging and supporting surface 64 cooperating with the surface on thebrake shoe to grip a strand therebetween. The brake member is springloaded into strand gripping relationship with the strand guide by meansof a spring 66, and a stop 68 projects from the base plate and isengaged by the brake lever 54 when the brake member is in grippingrelationship with the strand guide 62. Stop pin 68 also preventscomplete or partial unwinding of the spring by stopping the lever 54.The user is thus prevented from unwinding spring 66 by operating thelever 54 in the wrong direction during loading.

With this construction, and as best seen in FIG. 3 of the drawings, astrand 10 is trained through the strand brake 40 and the strand clamp inthe direction indicated by the arrow in FIG. 3. The pivotal attachmentof the base plate to the portion 42 allows the strand guide to alignitself automatically to accommodate any divergency in the approach ofthe strand to the strand clamp.

The strand 10 is free to move between the opposed surfaces of the brakeshoe and the strand guide and through the strand groove in the strandclamp in the direction indicated by the arrow. However, retrogrademovement of the strand in the opposite direction is resisted by thestrand brake, thereby automatically preventing sagging of the messenger.

While the pivotal brake described above will usually be preferable inthat it provides automatic alignment of the strand guide, wherealignment is not a problem the relatively simpler construction shown inFIG. 5 of the drawings may be utilized. Thus, as seen in FIG. 5 of thedrawings, the strand brake 70 includes a clamp engageable portion 72 towhich is fixed a base plate 74.

The portion 72 is provided with openings in the form of notches 76, 78and 80 to receive the bolts 24 and 32 of the strand clamp. The cableguide in this version may consist of simply a plate 82 fixed to andprojecting from the base plate 74 and having a cable engaging andsupporting surface 84. A brake member consisting of a lever 86 and ashoe 88 is pivotally mounted on the base plate at 90 and the strandengaging surface 92 of the shoe 88 is urged toward the surface 84 bymeans of a spring 94.

A pin 96 is welded to the plate 74 and serves as a stop, similarly tostop pin 68. Aside from the differences in construction between thepreviously described embodiment and that shown in FIG. 5 of thedrawings, the strand brake 70 is attached to the strand clamp 16 andfunctions similarly to the strand brake 40.

In both embodiments it will be noted that the brake assembly of thepresent invention provides a relatively simple, inexpensive mechanismfor preventing sag during messenger strand pulling operations.

While the forms of apparatus herein described constitute preferredembodiments of the invention, it is to be understood that the inventionis not limited to these precise forms of apparatus, and that changes maybe made therein without departing from the scope of the invention.

What is claimed is:

1. A strand brake assembly comprising:

a. a clamp engageable portion,

b. a strand clamp including opposed clamp plates,

0. means clamping said clamp engageable portion between said clampplates,

d. a base plate attached to and projecting from said clamp engageableportion,

e. a strand guide mounted on said base plate and including at least onestrand engaging and supporting surface,

f. a brake member pivotally mounted on said base plate for gripping incooperation with said strand guide surface a strand disposedtherebetween, and

g. means urging said brake member into strand gripping relationship tosaid strand guide surface.

2. The assembly of claim 1 further comprising:

a. stop means projecting from said base plate, en-

. gageable by said brake member when in said strand grippingrelationship to said strand guide surface and preventing rotation ofsaid lever past a presele'cted point.

3. The assembly of claim 1 wherein said brake member comprises:

a. a lever pivotally mounted on said base plate, and

b. a brake shoe mounted on said lever and having a strand engagingsurface opposing said surface of said strand guide.

4. The assembly of claim 1 wherein:

a. said base plate is pivotally attached to said clamp engageableportion for pivotal movement about an axis substantially normal to astrand supported by said strand guide.

5. The assembly of claim 1 wherein:

a. said base plate is fixedly attached to said clamp engageable portion.

6. The assembly of claim 1 wherein:

a. said clamping means comprises bolts extending through said clampplates, and

b. said clamp engageable portion has openings therein receiving saidbolts.

7. The assembly of claim 6 wherein:

a. said openings in said clamp engageable portion comprises notches.

8. The assembly of claim 1 wherein:

a. said clamp plates have portions defining a strand groovetherebetween, and

b. said strand groove is positioned to support a strand therein insubstantially the same plane as said strand guide.

9. The assembly of claim 8 wherein:

a. said clamp engageable portion received between said clamp platesspaces said clamp plates sufficiently to allow a strand to be retainedin but slidable in said strand groove.

1. A strand brake assembly comprising: a. a clamp engageable portion, b.a strand clamp including opposed clamp plates, c. means clamping saidclamp engageable portion between said clamp plates, d. a base plateattached to and projecting from said clamp engageable portion, e. astrand guide mounted on said base plate and including at least onestrand engaging and supporting surface, f. a brake member pivotallymounted on said base plate for gripping in cooperation with said strandguide surface a strand disposed therebetween, and g. means urging saidbrake member into strand gripping relationship to said strand guidesurface.
 2. The assembly of claim 1 further comprising: a. stop meansprojecting from said base plate, engageable by said brake member when insaid strand gripping relationship to said strand guide surface andpreventing rotation of said lever past a preselected point.
 3. Theassembly of claim 1 wherein said brake member comprises: a. a leverpivotally mounted on said base plate, and b. a brake shoe mounted onsaid lever and having a strand engaging surface opposing said surface ofsaid strand guide.
 4. The assembly of claim 1 wherein: a. said baseplate is pivotally attached to said clamp engageable portion for pivotalmovement about an axis substantially normal to a strand supported bysaid strand guide.
 5. The assembly of claim 1 wherein: a. said baseplate is fixedly attached to said clamp engageable portion.
 6. Theassembly of claim 1 wherein: a. said clamping means comprises boltsextending through said clamp plates, and b. said clamp engageableportion has openings therein receiving said bolts.
 7. The assembly ofclaim 6 wherein: a. said openings in said clamp engageable portioncomprises notches.
 8. The assembly of claim 1 wherein: a. said clampplates have portions defining a strand groove therebetween, and b. saidstrand groove is positioned to support a strand therein in substantiallythe same plane as said strand guide.
 9. The assembly of claim 8 wherein:a. said clamp engageable portion received between said clamp platesspaces said clamp plates sufficiently to allow a strand to be retainedin but slidable in said strand groove.